If Jason Estrada comes to fight that will be one big hurdle for Povetkin to jump over. I don't know if Povetkin learned anything from his experience with Eddie Chambers, but Chambers showed the world just how easy Povetkin is to hit. You can bet that Estrada will hit him too.
If he beats Povetkin, he can start making a lot of noise about Klitschko and will probably get a shot at the title. Of course that is all rather theoretical. Estrada may have the talent to beat Povetkin but getting by Povetkin's relentless, high pressure style won't be so easy. He lacks Povetkin's consistency.